1. Technical Field
Embodiments of the present invention generally relate to a sensing module and an angular velocity sensor having the same.
2. Description of the Related Art
Unless otherwise indicated herein, the materials described in this section are not prior art to the claims herein and are not admitted to be prior art by inclusion in this section.
Recently, an angular velocity sensor has been used in various applications including, for example, military applications such as an artificial satellite, a missile, an unmanned aircraft, vehicle applications such as an air bag, electronic stability control (ESC), a black box for a vehicle, hand shaking prevention for a camcorder, motion sensing for a mobile phone or a game machine, navigation, or the like.
The angular velocity sensor generally adopts a configuration in which a mass body is adhered to an elastic substrate such as a membrane, in order to measure angular velocity. Through the configuration, the angular velocity sensor may calculate the angular velocity by measuring Coriolis force applied to the mass body.
An exemplary scheme of measuring angular velocity using the angular velocity sensor is as follows. First, the angular velocity may be calculated using the Coriolis force represented by the equation F=2mΩ×v, where F denotes the Coriolis force applied to the mass body, m denotes the mass of the mass body, Ω denotes the angular velocity to be measured, and v denotes the motion velocity of the mass body. Since the motion velocity v and the mass m of the mass body are already known values, the angular velocity Ω can be calculated by detecting the Coriolis force (F) applied to the mass body.
The angular velocity sensor includes a piezoelectric material disposed on a membrane (a diaphragm) in order to drive a mass body or sense displacement of the mass body. In order to measure the angular velocity using the angular velocity sensor, the resonant frequency in a driving mode may be substantially matched with the resonant frequency in a sensing mode.